ANDROLOGY CORE B: The diagnostic Andrology resources available to the project leaders is among the most skilled and comprehensive collection of sperm function tests in the world, because many of these diagnostic tests are not widely utilized with the advent if in vitro fertilization and intracytoplasmic sperm injection. However, these assays are extremely advantageous to use for screening to identify the best small molecule inhibitor of ADCY10 for contraceptive development. The Andrology Core performs routine semen analysis and strict morphology according to WHO5 specifications, as well as tests of functional changes of sperm associated with capacitation: the acrosome reaction assay, Cap-Score, Zona-binding assay and sperm penetration assay as well as hyperactivated motility. Other specialized services not described are available to Andrology Core investigators. Specifically, the Andrology Core aims are: Aim #1: To recruit and retain fertile control men to serve as semen donors, who will collect semen for use in screening tests of candidate male contraceptive agents acting to inhibit ADCY10 and other allosteric inhibitors for sperm forms of sAC. Routine semen analysis (liquefaction, appearance (color), volume, viscosity, agglutination, aggregation, motility, count/density, other cells present (round cells), morphology, vitality ) will be used together with history and physical exam to select donors. Aim #2: To perform functional tests associated with capacitation. Tests of capacitation to be performed include the routine and induced acrosome reaction test, the CaPScore, zona binding and/or zona free hamster oocyte assays, hyperactivated motility assessment to test the candidate contraceptive agents for inhibition of sperm capacitation.